1. Technical Field
The present invention relates generally to the field of assessing human competence and more specifically to assessing human competence on man-made machines using non-verbal testing methods.
2. Prior Art
The best-known test of driver competence is the Useful Field of View (UFOV) test that recently has been implemented on a personal computer. Ball, K. and Owsley, C., Identifying correlates of accident involvement for the older driver, Human Factors, 33(5), 583–595. The basic task has the subject indicate the presence or absence of a stimulus in a visual field that can include a silhouette of a car or truck. The duration and/or intensity of the stimulus is manipulated so as to determine a detection threshold value. In validation trials, almost exclusively with elderly drivers, the threshold has been shown to be significantly correlated with the probability of a collision.
The present invention differs significantly from UFOV on two key points. First, the present invention uses absolute and relative response rate rather than stimulus threshold as the primary dependent variable. Second, the present invention's key measure of competence, a favorable interaction between channel capacity (CC) and situational awareness (SA), is taken throughout the range of CC. Since CC is correlated with age, fine distinctions in crash proneness can be determined at all age levels. UFOV measures a minimal necessary threshold for crash avoidance, which may indeed be workable for assessing older drivers. Indeed, UFOV has been exclusively validated on elderly drivers. Importantly, one would not expect that UFOV would make fine distinctions in crash proneness among younger drivers who have much faster response speed than the elderly.
Trails B is a public domain test that was originally part of the Army Individual Test Battery (1944) and later a standard component of the popular Halstead-Reitan Neuropsychological Test Battery (Halstead, 1947; Reitan & Davison, 1974). The Trails B test is still commonly used for the diagnosis of certain types of neuropathology and has been shown to predict crash proneness in a motor vehicle. Computer-based versions of the Trails B have been tested, especially for the evaluation of older drivers.
The present invention differs from Trails B in four fundamental ways. First, the adult Trails B has 25 letters and numbers whereas the present invention has 15. The choice of 15 letters and numbers adds to the sensitivity of the present invention and was empirically determined. Fewer than 15 such points is too low a workload, creating a ceiling effect in response speed among subjects. More than 15 points per page creates a floor effect among subjects. Second, Trails B is a single page of letters and numbers whereas the present invention includes four pages, the last of which has interspersed distracting pictures. Third, Trails B subjects are coached one-on-one through the making of the trail (and are required to correct errors and omissions) whereas the present invention has subjects read the instructions and then commence unassisted. Fourth, the key datum for Trails B is simply the time to complete the full (corrected) trait; there is no measure of the person's response variability. The present invention, on the other hand, includes the number of letters and numbers traversed per second (speed) on each of the four pages. This allows a measure of both absolute response speed and variability among pages.
CogScreen is an aviation related computer-administered and scored cognitive-screening instrument designed to assess deficits or changes in attention, immediate- and short-term memory, visual perceptual functions, sequencing functions, logical problem solving, calculation skills, reaction time, simultaneous information processing abilities, and executive functions. CogScreen has 95 scales, takes 45 minutes to an hour to administer, and lacks the sensitivity of the present invention (especially in the upper reaches of ability where pilots are over-represented).
Thus it can be seen that there exists a need for a valid, simple-to-administer, flexible, brief, assessment test for determining the ability of humans to operate man-made machines. It is to this need that the present invention is directed.